1. Field of the Invention
The present invention relates to a bottom frame structure for a playpen.
2. Description of the Related Art
A conventional bottom frame structure for a playpen in accordance with the prior art shown in FIG. 1 comprises a joint base 20 pivotally mounted between two rods 10 whereby the two rods 10 can be pivoted relative to each other so as to fold the bottom frame structure of the playpen. However, the bottom frame structure is not provided with any positioning device so that it is easily folded by an external force, thereby easily causing danger to the baby placed in the playpen.
In accordance with one aspect of the present invention, there is provided a bottom frame structure for a playpen comprising: four upright rods, a bottom frame, a positioning base, and a top frame, wherein,
the four upright rods are respectively located at four corners of the playpen for supporting and linking between the bottom frame and the top frame, two of the upright rods having a lower end secured with an inverted L-shaped support base, and the other two of the upright rods having a lower end secured with an inverted L-shaped wheel base having a roller;
the bottom frame is mounted on the lower end of the four upright rods and includes four first rods, two Y-shaped first connecting bases, four universal joints, four second rods, two T-shaped second connecting bases, and four third rods,
the four first rods each having a first end respectively pivoted to the horizontal section of the two support bases and the two wheel bases,
each of the two Y-shaped first connecting bases having three radially arranged pivot grooves and having a bottom secured with a resting post for supporting the first connecting base, two of the three pivot grooves of each of the two Y-shaped first connecting bases pivotally receiving a second end of each of the four first rods,
each of the four universal joints including a sleeve secured on a mediate portion of each of the four first rods, and a U-shaped pivot section which is rotatable toward any direction,
each of the four second rods having a first end pivoted to the pivot section of each of the four universal joints so that the four first rods and the four second rods form a rectangular frame,
each of the two T-shaped second connecting bases having three pivot slots and having a bottom secured with a resting rod for supporting the second connecting base, two of the pivot slots of each of the two T-shaped second connecting bases being in line with each other and each pivotally receiving a second end of each of the four second rods,
the four third rods being arranged between the first rods and the second rods in a cross intersecting manner, two of the four third rods having a first end pivoted to the pivot groove of each of the two first connecting bases and a second end connected to the positioning base, and the other two of the four third rods having a first end pivoted to the pivot slot of each of the two second connecting bases and a second end connected to the positioning base;
the positioning base is used to link the four third rods and includes a cruciform body, four fitting rod members, four U-shaped urging drive blocks, four elastic members, and a release block,
the body including four chambers each having an opening directed downward for receiving the second end of each of the four third rods, each of the four chambers having two side walls each defining a substantially L-shaped slide slot having an oblique upper end and a horizontal lower end and a circular hole located beside the horizontal lower end, the body having a top formed with four inclined surfaces each defining a rectangular slot connecting to each of the four chambers, and having a bottom secured with an abutting column,
each of the four fitting rod members having a first end provided with an insertion section secured and locked in the second end of each of the third rods by a threaded rod engaged with a nut, and a second end provided with a snap abutting section defining a transverse through hole and provided with an L-shaped snap abutting recess, a rivet pin in turn extending through the circular hole of each of the four chambers of the body and through the through hole of the snap abutting section of each of the four fitting rod members, so that each of the four fitting rod members is pivoted to each of the four chambers of the body,
each of the four urging drive blocks having two side walls each defining a circular hole and having a top portion provided with a rectangular bar having an upper section protruding outward from the rectangular slot of the body and defining a through hole, a lock pin in turn extending through the slide slot of the body and through the circular hole of each of the four urging drive blocks, so that the lock pin is detachably rested on the snap abutting recess of each of the four fitting rod members,
each of the four elastic members is mounted around the rectangular bar of each of the four urging drive blocks and having a lower end pressing the top portion of each of the four urging drive blocks and an upper end pressing an upper wall of each of the four chambers of the body, and
the release block movably mounted on the body and defining two spaced slot holes for allowing passage of a loop-shaped lift strap, the release block having four sides each provided with two spaced abutting plates rested on each of the four inclined surfaces of the body, the rectangular bar of each of the four urging drive blocks being received between the two abutting plates, each of the abutting plates defining a circular hole aligning with the through hole of the rectangular bar of each of the four urging drive blocks, a pivot rod in turn extending through the circular hole of each of the abutting plates and through the through hole of the rectangular bar, thereby pivoting the rectangular bar to the abutting plates of the release block.
The primary objective of the present invention is to provide a bottom frame structure for a playpen, wherein, the positioning function of the bottom frame can be used to control the folding and expanding actions of the skeleton of the playpen, thereby preventing the skeleton of the playpen from being easily folded due to the hit of an external force so as to protect the safety of the playpen.
Another objective of the present invention is to provide a bottom frame structure for a playpen, wherein, the support points and the connection points of the skeleton of the playpen have a rigid strength, thereby enhancing the loading and supporting strength of the playpen.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.